The CEO said Britain’s decision to Brexit from the European Union was not a good one and companies were working on contingency plans to “avoid the damage.”

Speaking to CNBC, Mr Moynihan said: “I think it’s not good because at the end of the day, without Brexit hanging over our head, we would just be plugging away, working for customers, adding people, bringing our Summer teammates into London.

“All that gets pulled into question. it’s not good. There’s no upside here, just attempts to avoid the damage.”

US bank executives signalled early on their support for the Remain vote but have spent the months since the Brexit vote preparing their businesses for the new political situation.

Bank of America announced in July 2017 it would move its European operations out of London to Dublin.

The Irish capital is emerging as a top destination for businesses seeking post-Brexit relocation alongside the German business hub of Frankfurt.

Felix Hufeld, the president of Germany’s top financial regulator BaFin, said the watchdog will deal with requests to establish hubs on a “first come, first served” basis, hinting banks hoping to relocate need to do so before the Brexit deadline.

Mr Hufeld believes the European Union should prepare for a hard Brexit because “negotiators have not made sufficient progress on the designated key separation issues”.

He said: “One thing that we will not accept under any circumstances is empty shells or what we call letterbox models.

“Banks that are planning a comprehensive division of work between offices in London and the EU need to transplant and split up their entire ecosystem established over the years – that means IT infrastructures, knowledge, processes and people.”

Lobby group Frankfurt Main Finance forecasted earlier this year that around 10,000 bankers will migrate out of London to Germany because of Brexit.

Goldman Sachs chairman Llyod Blankfein strengthened the group’s prediction, writing on Twitter: “Just left Frankfurt. Great meetings, great weather, really enjoyed it. Good, because I’ll be spending a lot more time there. #Brexit.”